Type bar operating mechanism for typewriters



March 27,1945. P. J. THYER 2,372,616

TYPE BAR OPERATING MECHANISM FOR TYPEWRITERS- Filed Dec. 8, 1945 2 Sheets-Sheet 1 Mai-ch 27,1945. P, THYER 2,372,616

TYPE BAR OPERATING MECHANISM FOR TYPEWRITERS Patented Mar. 27 1945 TYPE BAR OPERATING MECHANISM FOR TYPEWRITERS Percy John Thyer, Nottingham, England Application December 8, 1943, Serial No. 513,405 In Great Britain May 27, 1942 8 Claims;

This invention relates to improvementsv in the type bar operating mechanism of typewriters of the kind in which the type bars are mounted on a segment which is raised and lowered by the shift mechanism to bring the lower or upper case of type into operative position as required.

The object of the present invention is to pro' vide simple mechanism for operating th type bars and reduce to a, minimum the weight of the parts which have to be moved when changing from one case of type to the other.

According to the present invention the type bars are pivoted on a segment and connected by links to sub-levers pivoted on the key levers and maintained in the same or substantially the same position relatively to the key levers during the movement of the latter to operate the type bars. A further feature of the invention is the provision of projections or cam surfaces on the links connected to the type bars to engage with andoperate the bail.

The invention will now be more particularly described with reference to the accompanying drawings in which: i

Fig. l is a side elevation of type bar operating mechanism constructed according to the invention, I

Fig. 2 is a side elevation of an alternative construction,

Fig. 3 is a rear elevation of part of the type bar segment showing the connection between the type bar and key levers, and

Fig, 4 is a side elevation of part of the mechanism shown in Fig. 2.

Figs. 3 and 4 are drawn to a larger scale than the remaining figures.

Like letters indicate like parts throughout the drawings.

In carrying out this invention the type bars A are pivoted in well known manner in saw gates in a segment B which is mounted in any convenient manner so that by angularly adjusting thetype bars the type carried thereby can be moved into engagement with the platen C of the machine and by raising and lowering the segment Bthe lower or upper case of type engages with the platen C when the type bars A are operated.

The type bars A are connected by one or more links D to one end of sub-levers E which are pivoted at their other ends to the key levers F which are pivoted at their rear ends F to the fixed framing of the machine. It will be seen that with this arrangement the segment B carrying the type bars A can be raised and lowered as desired, movement of the segment merelyaltering the position of the sub-leverE. relatively to that of the key lever F as indicated in dotted lines in Figs. 1 and 4. It will however be understood that in order to operate the type bars A by depression of their associated key levers F provision must be made for locking or holding the sub-levers E in'the same or substantially the same position relatively to the key levers during the movement of th latter and when the type bar segment is in its higher or lower position.

When the segment B is in its highest position the sub-lever E is in its highest position relatively to the key lever and the sub-lever may be retained in the same relative position during the depression of the key lever by a pin or stop on the latter engaging the upper edge of the sublever.

When the type bar segment is moved into its lowest position the sub-lever will be angularly adjusted about its pivot, as the normal position of the key levers will remain unaltered, and will consequently be moved away from the pin or stop previously described. In order therefore to lock the sub-levers in position the following arrangement is adopted. Each sub-lever E is provided with a tail G (see Fig. 1) and this tail may be disposed as shown at the end of the sub-levers where it is pivoted to the key lever F, or in any other convenient position. A universal bar or roller H is provided and this bar is moved into engagement with the tails G on the sub-levers E by the shift mechanism when the latter is operated to lower the type bar segment B. It will be apparent by reference to Figure 1 of the drawings that the bar H is connected to the type bar,

segment B by a bell crank lever means X pivotally mounted as at Y and having one arm extension means connected with said bar H and the other arm extension means slot and pin connected as at Z to the segment B so that when the shift mechanism is operated to move said type bar segment, the bar H is automatically adjusted in the manner stated. When the key levers are depressed the tails G slide on the universal bar and they are so shaped that the sub-levers are retained in the same or substantially the same position relatively to the key levers during the movement of the latter. If preferred a similar ar' rangement may be adopted instead of providing stops on the sub-levers for use when the segment is in its highest position as shown in Fig. 1 and the shift mechanism adapted to adjust the position of the universal bar H to co-operate with the same tall or an additional tail and universal bar may be provided. As shown in Fig. 1 the sublever E is moved into the position indicated by dotted lines when the type bar segment is lowered to bring the upper case into operation and the bar or roller H is adjusted at the same time into the position shown in dotted lines.

The links D which connect the type bars to the sub-levers E may be connected to the latter as shown in Fig. l or may be pin jointed to the latter and may be provided at their upper ends with openings which engage with arms A on the type bars A. These arms A are provided with hook,

shaped extremities A which are engaged by the ends of the links D just before the completion of the angular motion of the type bars to give a final accelerated motion to the latter just before engaging the platen C.

At the extreme ends of the type bar segment the position of the type bars is suchthat they do not lend themselves very readily to operation by a direct pull from the sub-levers. Accordingly the ends of the type bars may be provided with openings therein through which the links can slide and the latter be so shaped as to impart the necessary motion to the type bar.

The links 1) may further be provided with projections D to engage with an operate the bail K instead of the latter being operated as hitherto by the type bars so that there is nothing tending to obstruct the angular motion of the type bars.

Springs are provided to return the key levers to their normal positions and these springs may be disposed around the links D previously described and have their upper ends connected to the link and their lower ends engaging a stop.

Preferably however the springs are connected be- 5 tween the key levers and the fixed frame and between the type bars and fixed frame as shown. as in the first mentioned case provision has to be made for altering the position of the stop with alterations in the position of the type bar segment and consequently means an increase in the weight of the moving parts.

The key levers F may be provided with exten sions F adapted to engage with a universal bar L when depressed and adjust the latter to operate the ribbon feed.

As is well known the keys of typewriters are arranged in banks and consequently with a uniform key depression the angular displacement of the key levers will vary slightly according to the length of the key levers. In order to compensate for the variation in the angular movement of the key levers and obtain the correct movement of the type bars the tails G on the sublevers E are shaped sothat as the key levers are depressed the sub-levers are given a slight movement relatively to the key levers sufiicient to compensate for the variation in the angular movement of the key levers. If desired the tails G may be shaped so as to provide a slight additional movement of the sub-levers to give an increasing acceleration to the type bars from their position at rest up to the platen when the key levers are depressed.

In the preferred construction shown in Figs. 2 and 3 the type bar levers A are connected to the sub-levers E by a link or links D as shown. The sub-levers E are formed with extensions E preferably disposed at the end where the sub-lever is pivoted to the key lever F and in order toretain the sub-lever in the same or substantially the same position relatively to the key lever the following arrangement is adopted. The upper end of the extensions E on the sub-levers E are con-- nected by link's E to a bar E extending across the bank of key levers. It will therefore be seen that when the key levers F are depressed the links E will turn about the bar E and maintain the sub-lever in the same or substantially the same relative position with its associated key lever when the latter is depressed.

In order to adjust the position of the sub-levers when changing from the lower to the upper case of type the barE is carried at each end by one arm of a bell crank lever B pivoted at E to the fixed frame the other arm of which is connected to the type bar segment so as to be adjusted thereby when the latter is raised or lowered. As shown more clearly in Fig. 4 the position of the sub-levers and connecting links when the type .bar segment is in its highest position is shown in full lines. When the type bar segment is lowered the bell crank levers E are adjusted to the position shown in dottedlines with a consequent movement of the sub-lever E into the position indicated in dotted lines without any alterations in the position of the key levers F.

As will be well understood the angular disposition of the type bars A at the sides of the type bar segment and clearly shown in Fig. 3 does not allow of their easy operation by a direct connection between the type bars and the sublevers. In order therefore to operate the type bars at the sides where the angular difference between the planes of operation of the type bars and sub-levers prevents the easy operation of the type bars by a direct connection between the latter and the sub-levers the links D are divided into two parts and adjacent ends of the two parts being connected to arms D pivoted to a segment D secured to the type bar segment B. The arms D are disposed so that the links D connecting the arms to the key levers and type bars are disposed in the plane of operation of the key levers and type bars respectively so that movement of the links D is substantially longitudinal and lateral movement is reduced to a minimum. When. the links D are divided into two parts the uppermost may be formed with a raised part D to operate the bail K as shown in Fig. 3 or if preferred the bail may be operated from the lowermost links by an alteration in the disposition of .the bail as shown in Figs. 1 and 2.

With the arrangement described the Weight of the parts which it is necessary to move when changing from one case of type to the other are reduced to a minimum. The type bars only have their normal function to perform and there is nothing tending to restrict their motion and the initial movement of the key levers is devoted solely to the initial movement of the type bars from rest. If desired the connection to the sublevers adapted to retain them in the same or substantially the same position relatively to the key levers may be arranged so that as the key levers are depressed a slight variation in the relative positions of the key levers and sub-levers is produced and adapted to give an increasing acceleration of the type bars from their position at rest up to the position where they engage with the platen.

The correct movement of the type bars for a uniform depression of the keys is obtained by a variation in the length of the extensions E on the sub-levers E attached to the key levers in the different banks so as to provide a movement of the sub levers relatively to the key levers sufficient to compensate for the variation in the angular displacement of the key levers in the difierent banks writers comprising pivoted type bars, links to connect the type .bars to sub-levers pivoted on key levers, tails on the sub-levers and abar to engage with the tails and hold the sub-levers in the same or substantially the same position relatively to the key levers during the movement of the latter to operate the type bars.

3. Type bar operating mechanism of typewriters comprising type bars pivoted on a segment, links to connect the type bars to sub-levers pivoted on key levers, tails on the sub-levers, a bar to engage with the tails and hold the sublevers in thesame or substantially the same position relatively to the key levers during the movement of the latter to operate the typ bars and means to adjust the position of the bar when the type bar segment is raised or lowered to bring the upper or lower case into operative position.

4. Type bar operating mechanism of typewriters comprising pivoted type bars, links to connect the type bars to sub-levers pivoted on key levers and extensions on the sub-levers jointed to links pivoted on a bar disposed so that the sublevers are held in thesame or substantially the same position relatively to the key levers during the movement of the latter to operate the type bars.

5. Type bar operating mechanism of typewriters comprising type bars pivoted on a segment, links to connect the type bars to sub-levers pivoted on key levers, extensions on the sub-levers jointed to links pivoted on a bar disposed so that the sub-levers are held in the same or substantially the same position relatively to the key levers during the movement of the latter to operate the type bars and means to adjust the position of. the bar when the type bar segment is raisedor lowered to bring the upper or lower case into operative position.

6. Type bar operating mechanism of typewriters comprising type bars pivoted on a segment, links to connect the type bars to sub-levers pivoted on key levers, extensions on the sub-levers jointed to links pivoted on a bar disposed so that the sub-levers are held in the same or substantially the same position relatively to the key levers when the latter are moved to operate the key levers and bell crank levers, the ends of which are connected respectively to the bar and type bar segment to adjust the position of the bar when the type bar segment is raised and lowered.

'7. Type bar operating mechanism of typewriters comprising pivoted type bars, links to connect the type bars to sub-levers pivoted on key levers, means to hold the sub-levers in the same or substantially the same position relatively to the key levers when the latter are moved to op- 'erate the type bars and extensions on the key levers adapted to engage with and move a universal bar to actuate the ribbon feed.

8. Type bar operating mechanism for typewriters comprising pivoted type bars, links to connect the type bars to sub-levers pivoted on key levers, means to hold the sub-leversin the same or substantially the same position relatively to the key levers whenthe latter are moved to operate the type bars, raised parts on the links and a bail to actuate the ribbon feeding mechanism so disposed that the raised parts engage withand operate the bail when the key levers are moved to operate the type bars.

PERCY JOHN THYER. 

